The answer to: How do you set directories to 755 and files to 644?

AKA: Choosing and setting safe file permissions for a WordPress install.

If you have ever watched a WordPress security presentation, you’ve heard the advice:

Generally speaking, directories should be 755 and files should be 644.

But the presenter never tells you how to change these settings for all the directories and files in the WordPress install. I’m guilty of the same thing in my presentation.  After all, Bash doesn’t go over well in front of general audiences.

But how do you change all the directories and files to have the settings that you want? You’re certainly not going to go around and manually change all of the permissions file by file & directory by directory!  And if you did, would you still be able to upload files and upgrade your plugins with those permissions? Probably not.

I thought I would share how I handle this on my servers.  My method is not the most refined, and does have some minor issues, but it works and gets me 95% to where I should be.

I have this function built into my .bashrc file:

function defaultr()
{
find . -type d | xargs chmod -v 755
find . -type f | xargs chmod -v 644
find . -type d -iname uploads | xargs chmod -Rv 774
find . -type d -iname blogs.dir | xargs chmod -Rv 774
find . -type d -iname cache | xargs chmod -Rv 774
find . -type d -iname themes | xargs chmod -Rv 774
find . -type d -iname plugins | xargs chmod -Rv 774
find . -type d -iname upgrade | xargs chmod -Rv 774
}

It is meant to be run from a www or public_html directory with WordPress installed under it.  This will follow the basic rule, and modify the special directories so that you can upload, upgrade and use a caching tool.  Additionally, it works for WordPress with multi-site either enabled or disabled.
Now, if you wanted to have some real fun, you could add lock and unlock functions so that there can be no changes to your plugins and themes unless you want them to be changed and then your site IS secure.

function lock()
{
find . -type f -iname wp-config.php | xargs chmod -Rv 644
find . -type d -iname themes | xargs chmod -Rv 754
find . -type d -iname plugins | xargs chmod -Rv 754
find . -type d -iname upgrade | xargs chmod -Rv 754
}

function unlock()
{
find . -type f -iname wp-config.php | xargs chmod -Rv 774
find . -type d -iname themes | xargs chmod -Rv 774
find . -type d -iname plugins | xargs chmod -Rv 774
find . -type d -iname upgrade | xargs chmod -Rv 774
}

Of course that means you need to be confident and not panic when you see messages like “Cannot update/modify/create x” and remember to unlock things before making those changes, but largely, you can set and forget these things until you are ready to apply updates.

One final note. The numbers in these examples are suitable for many shared hosts. If you pay more than $10/month for hosting, chances are you will be able to changes those numbers to better suit your needs. When I lock the files down, I use 544 and sometimes lower.

In any case, this is a good baseline for your functions and will get the job done.  If you have a similar/better technique, I’d love to hear it.

(BTW have you figured out where the flaws are?)

Addendums:

• I should mention that the settings here are verbose.  You can change the -Rv to -Rcf or just -Rf and get the same results less space taken up.
• If you get an error like “chmod: missing operand after ‘744’” This is “normal”. It just means that your install does not have one of the directories. Maybe you’ve never upgraded a plugin and the upgrade directory doesn’t exist. Or you have never run multisite and blogs.dir does’t exist.  You can either remove these lines or create empty directories, if the errors bother you.
• I’ve added echo lines so I can determine which commands create errors